■ Figure 1. Sorting of cpTAT Substrates in the Stroma through Liquid–Liquid Phase Transition.
cpTAT substrates are imported into chloroplasts through the general TOC-TIC translocons, followed by cleavage of the N-terminal TP (transit peptide).
After import, complex formation occurs among a cpTAT substrate, STT1, and STT2 through multivalent interactions, facilitating liquid–liquid phase
transition. For engagement of the cpTAT substrate with the TAT transport system at thylakoid membranes, an electrostatic interaction occurs between
STTs and Hcf106, thereby releasing the cpTAT substrate and leading to import into the thylakoid lumen.